A short piece of this character may also have a slit cut into one end, instead of a hollow made with a fuller. If a slit is made, it is necessary to drive a thick wedge into the opening to make it several inches in width, previous to upsetting; if the gap is not well opened with a wedge, or by sledge-hammering while across an anvil, the blows of the hammer will shorten the work, without producing the head or T-form that is desired.

Another method of making a large T-end consists in laying and welding two bars together as in Fig. 150. The bars are thoroughly welded in the intermediate portion, but not at the two ends; these are opened, and one pair formed into a T, and the other two ends are shaped for becoming part of a tongue-joint, by which the T-portion is welded to the remainder of the rod.

Either of these methods for making T-ends may be adopted, according to the resources of the maker; whether he has small iron or large at command, and whether he has a number of small remnants he may desire to forge.

When it is intended to forge the entire rod of one bar or piece, the necessary length of iron is discovered at the commencement of the forging, by applying, in a modified manner, the rule in page 8. Whether the original piece be four-sided or circular is of no consequence, if it is of good quality and of sufficient sectional area. When the intermediate part of the intended rod is to be of circular section, or what is commonly named round, a square bar is a very convenient one to commence with.

If we consider it stated that the intermediate part is to be circular, and its forged diameter to be 150 millimetres, the first step is to select a bar whose sectional area is about double or treble that of the intended mid-portion. The dimensions of the bar selected depends upon the intended length of the work. If the length of the intermediate is to be 1524 millimetres, the original piece selected may be 230 millimetres square.

The next step is to ascertain the length of iron required for the circular intermediate part; then discover the length required for the two T-portions, and add all together to indicate the total length requisite.

The bar selected being 230 millimetres square, its sectional area, 52900 millimetres, constitutes the first term of the proposition. And if the mean diameter of the intermediate part is to be

150 millimetres, its sectional area, 17671 millimetres, constitutes the second term of the proposition. The length of this part, 1524 millimetres, is the third term. The three terms, with the result, appear thus:

52900 : 17671 : : 1524 : 510, the fourth term denoting the length, in millimetres, of iron necessary; this result being obtained by multiplying the second and third terms together, and dividing by the first term, in the usual manner, avoiding minute fractions as of no use in this affair. The proper length of metal for the intermediate is thus found to be 510 millimetres, if the bar is 230 millimetres square, and therefore contains 52900 square millimetres in a sectional area.

The two T-parts next demand attention. These portions are sometimes short and thick; in such cases the amount of upsetting required is but small; but, whether little or much is needed, the requisite length of metal may be known by a little measurement. If it should be necessary to make the length of the T-part three times the length of the rod's diameter, the end may be either opened, spread out, and upset to 450 millimetres, or it may be spread out in an easier manner to the desired length, without upsetting; in which case the fibres of the head will be parallel to the rod's length, instead of at right angles to it, which is the preferable position.

To ascertain the length of bar that will be needed for the head or T-part, the rule is applied in a similar manner to that for the intermediate. If it is decided that the length of one head shall be 450 millimetres, and its sectional area 2 1000 millimetres, the necessary length of the original bar appears in the fourth term of the complete proposition, thus :

52900 : 20000 : : 450 : 171.

171 millimetres of the bar being sufficient for one head or T-piece, 342 millimetres are sufficient for both ; this length is therefore added to 510 millimetres for the intermediate, which result determines the total length of bar needed for one connecting-rod, to be 852 millimetres, if its sectional area previous to forging contains 52900 square millimetres.

Through the necessity of heating the iron a number of times, a portion will be taken from the lump by the fire, for which a few millimetres should be allowed, so that the length of bar actually required and used is about 900 millimetres.

After a lump of these dimensions is selected, the first step is to either spread out or upset both the T-parts; and when the desired shape of these ends is attained, the intermediate lump is reduced to its intended diameter.

This reducing is facilitated by the two hollows at the inner extremity of each head. The forged thickness of the head indicates the places for these hollows, shown in the Figure by H. Steam-hammer fullers are driven in to an equal distance from both sides, after which the work is lengthened and drawn down to its proper diameter.

To forge a connecting-rod in the manner indicated by Fig. 146, the proper quantity of iron necessary for each of the two pieces may be ascertained, and each piece separately forged to the required dimensions, and welded together at the conclusion.

Each of the pieces shown in the Figure is handled by a porter, marked P. These porters are round at that part which is supported by the endless chains, for the convenience of being easily rotated by the workmen. Fastened to a porter is seen a rotator, R, which is gripped by the men for the purpose of reversing or rotating the work.

The two pieces represented by Fig. 147 are nearly the shape of those in Fig. 146. The difference consists in the heads or T-parts being of greater relative dimensions because of more iron being required to surround the brasses. These brasses being circular, their recesses in the rods' ends may be formed by boring holes into the ends of the rods that are forged solid with the cap C, without any hole whatever.